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Determining if I am connected to the internet

Posted on 2000-01-06
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From VB, how can I determine if I am connected to the internet?  

I tried "InternetGetConnectedState" and that works fine except for AOL.

I was thinking about pinging some IP address and if I get a reply then I know I am connected.  But, is there some sort of api I can use to ping an IP.  Or is there a better way to find out if I am connected..
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Question by:Goob123
5 Comments
 
LVL 7

Expert Comment

by:kamall
ID: 2330691
Try this code:

   ' Registry APIs.
   Public Const HKEY_CLASSES_ROOT = &H80000000
   Public Const HKEY_CURRENT_USER = &H80000001
   Public Const HKEY_LOCAL_MACHINE = &H80000002
   Public Const HKEY_USERS = &H80000003
   Public Const HKEY_PERFORMANCE_DATA = &H80000004
   Public Const HKEY_CURRENT_CONFIG = &H80000005
   Public Const HKEY_DYN_DATA = &H80000006
   Public Const ERROR_SUCCESS = 0&
   Public Const APINULL = 0&
   Public Const MAX_STRING_LENGTH As Integer = 256


   Declare Function RegOpenKey Lib "advapi32.dll" Alias "RegOpenKeyA" (ByVal hKey As Long, ByVal lpSubKey As String, phkResult As Long) As Long


   Declare Function RegCloseKey Lib "advapi32.dll" (ByVal hKey As Long) As Long
       ' RegQueryValueEx: If you declare the lpData parameter as String,
       '    
       ' you must pass it By Value.


   Declare Function RegQueryValueEx Lib "advapi32.dll" Alias "RegQueryValueExA" (ByVal hKey As Long, ByVal lpValueName As String, ByVal lpReserved As Long, lpType As Long, lpData As Any, lpcbData As Long) As Long
       ' Remote Access Services (RAS) APIs.
       Public Const RAS_MAXENTRYNAME As Integer = 256
       Public Const RAS_MAXDEVICETYPE As Integer = 16
       Public Const RAS_MAXDEVICENAME As Integer = 128
       Public Const RAS_RASCONNSIZE As Integer = 412

 
   Public Function Connected_To_ISP() As Boolean


       Dim hKey As Long
       Dim lpSubKey As String
       Dim phkResult As Long
       Dim lpValueName As String
       Dim lpReserved As Long
       Dim lpType As Long
       Dim lpData As Long
       Dim lpcbData As Long
       Connected_To_ISP = False
       lpSubKey = "System\CurrentControlSet\Services\RemoteAccess"
       ReturnCode = RegOpenKey(HKEY_LOCAL_MACHINE, lpSubKey, phkResult)


       If ReturnCode = ERROR_SUCCESS Then
           hKey = phkResult
           lpValueName = "Remote Connection"
           lpReserved = APINULL
           lpType = APINULL
           lpData = APINULL
           lpcbData = APINULL
           ReturnCode = RegQueryValueEx(hKey, lpValueName, lpReserved, lpType, _
           ByVal lpData, lpcbData)
           lpcbData = Len(lpData)
           ReturnCode = RegQueryValueEx(hKey, lpValueName, lpReserved, lpType, _
           lpData, lpcbData)


           If ReturnCode = ERROR_SUCCESS Then

               If lpData = 0 Then
                   ' Not Connected
                   MsgBox "Not Connected To ISP."
               Else
                   ' Connected
                   Connected_To_ISP = True
                   MsgBox "Currently Connected To ISP."
               End If

           End If

           RegCloseKey (hKey)
       End If

   End Function


Regards.
0
 

Author Comment

by:Goob123
ID: 2330799
Sorry but this did not work.  I did run a registry monitor on AOL to see what it writes out and there was nothing usefull written to tell me it was connected.
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LVL 2

Accepted Solution

by:
winwiz earned 400 total points
ID: 2330885
This code may help:  it is code that will ping an IP address, if you determine a public ip address then customize this script you can find out if a net connection is present.  The code is as follows:

'1) Place a command button on the form and place this code in the Click event
   Dim ECHO As ICMP_ECHO_REPLY
   Dim pos As Integer
   
  'ping an ip address, passing the
  'address and the ECHO structure
   Call Ping("209.48.177.35", ECHO)
   
  'display the results from the ECHO structure
   Form1.Print GetStatusCode(ECHO.status)
   Form1.Print ECHO.Address
   Form1.Print ECHO.RoundTripTime & " ms"
   Form1.Print ECHO.DataSize & " bytes"
   
   If Left$(ECHO.Data, 1) <> Chr$(0) Then
      pos = InStr(ECHO.Data, Chr$(0))
      Form1.Print Left$(ECHO.Data, pos - 1)
   End If

   Form1.Print ECHO.DataPointer

'2) Add a .BAS module and paste this code in that module
'3) Click the command button
Option Explicit

Public Const IP_STATUS_BASE = 11000
Public Const IP_SUCCESS = 0
Public Const IP_BUF_TOO_SMALL = (11000 + 1)
Public Const IP_DEST_NET_UNREACHABLE = (11000 + 2)
Public Const IP_DEST_HOST_UNREACHABLE = (11000 + 3)
Public Const IP_DEST_PROT_UNREACHABLE = (11000 + 4)
Public Const IP_DEST_PORT_UNREACHABLE = (11000 + 5)
Public Const IP_NO_RESOURCES = (11000 + 6)
Public Const IP_BAD_OPTION = (11000 + 7)
Public Const IP_HW_ERROR = (11000 + 8)
Public Const IP_PACKET_TOO_BIG = (11000 + 9)
Public Const IP_REQ_TIMED_OUT = (11000 + 10)
Public Const IP_BAD_REQ = (11000 + 11)
Public Const IP_BAD_ROUTE = (11000 + 12)
Public Const IP_TTL_EXPIRED_TRANSIT = (11000 + 13)
Public Const IP_TTL_EXPIRED_REASSEM = (11000 + 14)
Public Const IP_PARAM_PROBLEM = (11000 + 15)
Public Const IP_SOURCE_QUENCH = (11000 + 16)
Public Const IP_OPTION_TOO_BIG = (11000 + 17)
Public Const IP_BAD_DESTINATION = (11000 + 18)
Public Const IP_ADDR_DELETED = (11000 + 19)
Public Const IP_SPEC_MTU_CHANGE = (11000 + 20)
Public Const IP_MTU_CHANGE = (11000 + 21)
Public Const IP_UNLOAD = (11000 + 22)
Public Const IP_ADDR_ADDED = (11000 + 23)
Public Const IP_GENERAL_FAILURE = (11000 + 50)
Public Const MAX_IP_STATUS = 11000 + 50
Public Const IP_PENDING = (11000 + 255)
Public Const PING_TIMEOUT = 200
Public Const WS_VERSION_REQD = &H101
Public Const WS_VERSION_MAJOR = WS_VERSION_REQD \ &H100 And &HFF&
Public Const WS_VERSION_MINOR = WS_VERSION_REQD And &HFF&
Public Const MIN_SOCKETS_REQD = 1
Public Const SOCKET_ERROR = -1

Public Const MAX_WSADescription = 256
Public Const MAX_WSASYSStatus = 128

Public Type ICMP_OPTIONS
    Ttl             As Byte
    Tos             As Byte
    Flags           As Byte
    OptionsSize     As Byte
    OptionsData     As Long
End Type

Dim ICMPOPT As ICMP_OPTIONS

Public Type ICMP_ECHO_REPLY
    Address         As Long
    status          As Long
    RoundTripTime   As Long
    DataSize        As Integer
    Reserved        As Integer
    DataPointer     As Long
    Options         As ICMP_OPTIONS
    Data            As String * 250
End Type

Public Type HOSTENT
    hName As Long
    hAliases As Long
    hAddrType As Integer
    hLen As Integer
    hAddrList As Long
End Type

Public Type WSADATA
    wVersion As Integer
    wHighVersion As Integer
    szDescription(0 To MAX_WSADescription) As Byte
    szSystemStatus(0 To MAX_WSASYSStatus) As Byte
    wMaxSockets As Integer
    wMaxUDPDG As Integer
    dwVendorInfo As Long
End Type


Public Declare Function IcmpCreateFile Lib "icmp.dll" () As Long

Public Declare Function IcmpCloseHandle Lib "icmp.dll" _
   (ByVal IcmpHandle As Long) As Long
   
Public Declare Function IcmpSendEcho Lib "icmp.dll" _
   (ByVal IcmpHandle As Long, _
    ByVal DestinationAddress As Long, _
    ByVal RequestData As String, _
    ByVal RequestSize As Integer, _
    ByVal RequestOptions As Long, _
    ReplyBuffer As ICMP_ECHO_REPLY, _
    ByVal ReplySize As Long, _
    ByVal Timeout As Long) As Long
   
Public Declare Function WSAGetLastError Lib "WSOCK32.DLL" () As Long

Public Declare Function WSAStartup Lib "WSOCK32.DLL" _
   (ByVal wVersionRequired As Long, _
    lpWSADATA As WSADATA) As Long
   
Public Declare Function WSACleanup Lib "WSOCK32.DLL" () As Long

Public Declare Function gethostname Lib "WSOCK32.DLL" _
   (ByVal szHost As String, _
    ByVal dwHostLen As Long) As Long
   
Public Declare Function gethostbyname Lib "WSOCK32.DLL" _
   (ByVal szHost As String) As Long
   
Public Declare Sub RtlMoveMemory Lib "kernel32" _
   (hpvDest As Any, _
    ByVal hpvSource As Long, _
    ByVal cbCopy As Long)


Public Function GetStatusCode(status As Long) As String

   Dim msg As String

   Select Case status
      Case IP_SUCCESS:               msg = "ip success"
      Case IP_BUF_TOO_SMALL:         msg = "ip buf too_small"
      Case IP_DEST_NET_UNREACHABLE:  msg = "ip dest net unreachable"
      Case IP_DEST_HOST_UNREACHABLE: msg = "ip dest host unreachable"
      Case IP_DEST_PROT_UNREACHABLE: msg = "ip dest prot unreachable"
      Case IP_DEST_PORT_UNREACHABLE: msg = "ip dest port unreachable"
      Case IP_NO_RESOURCES:          msg = "ip no resources"
      Case IP_BAD_OPTION:            msg = "ip bad option"
      Case IP_HW_ERROR:              msg = "ip hw_error"
      Case IP_PACKET_TOO_BIG:        msg = "ip packet too_big"
      Case IP_REQ_TIMED_OUT:         msg = "ip req timed out"
      Case IP_BAD_REQ:               msg = "ip bad req"
      Case IP_BAD_ROUTE:             msg = "ip bad route"
      Case IP_TTL_EXPIRED_TRANSIT:   msg = "ip ttl expired transit"
      Case IP_TTL_EXPIRED_REASSEM:   msg = "ip ttl expired reassem"
      Case IP_PARAM_PROBLEM:         msg = "ip param_problem"
      Case IP_SOURCE_QUENCH:         msg = "ip source quench"
      Case IP_OPTION_TOO_BIG:        msg = "ip option too_big"
      Case IP_BAD_DESTINATION:       msg = "ip bad destination"
      Case IP_ADDR_DELETED:          msg = "ip addr deleted"
      Case IP_SPEC_MTU_CHANGE:       msg = "ip spec mtu change"
      Case IP_MTU_CHANGE:            msg = "ip mtu_change"
      Case IP_UNLOAD:                msg = "ip unload"
      Case IP_ADDR_ADDED:            msg = "ip addr added"
      Case IP_GENERAL_FAILURE:       msg = "ip general failure"
      Case IP_PENDING:               msg = "ip pending"
      Case PING_TIMEOUT:             msg = "ping timeout"
      Case Else:                     msg = "unknown  msg returned"
   End Select
   
   GetStatusCode = CStr(status) & "   [ " & msg & " ]"
   
End Function


Public Function HiByte(ByVal wParam As Integer)

    HiByte = wParam \ &H100 And &HFF&

End Function


Public Function LoByte(ByVal wParam As Integer)

    LoByte = wParam And &HFF&

End Function


Public Function Ping(szAddress As String, ECHO As ICMP_ECHO_REPLY) As Long

   Dim hPort As Long
   Dim dwAddress As Long
   Dim sDataToSend As String
   Dim iOpt As Long
   
   sDataToSend = "Echo This"
   dwAddress = AddressStringToLong(szAddress)
   
   Call SocketsInitialize
   hPort = IcmpCreateFile()
   
   If IcmpSendEcho(hPort, _
                   dwAddress, _
                   sDataToSend, _
                   Len(sDataToSend), _
                   0, _
                   ECHO, _
                   Len(ECHO), _
                   PING_TIMEOUT) Then
   
        'the ping succeeded,
        '.Status will be 0
        '.RoundTripTime is the time in ms for
        '               the ping to complete,
        '.Data is the data returned (NULL terminated)
        '.Address is the Ip address that actually replied
        '.DataSize is the size of the string in .Data
         Ping = ECHO.RoundTripTime
   Else: Ping = ECHO.status * -1
   End If
                       
   Call IcmpCloseHandle(hPort)
   Call SocketsCleanup
   
End Function
   

Function AddressStringToLong(ByVal tmp As String) As Long

   Dim i As Integer
   Dim parts(1 To 4) As String
   
   i = 0
   
  'we have to extract each part of the
  '123.456.789.123 string, delimited by
  'a period
   While InStr(tmp, ".") > 0
      i = i + 1
      parts(i) = Mid(tmp, 1, InStr(tmp, ".") - 1)
      tmp = Mid(tmp, InStr(tmp, ".") + 1)
   Wend
   
   i = i + 1
   parts(i) = tmp
   
   If i <> 4 Then
      AddressStringToLong = 0
      Exit Function
   End If
   
  'build the long value out of the
  'hex of the extracted strings
   AddressStringToLong = Val("&H" & Right("00" & Hex(parts(4)), 2) & _
                         Right("00" & Hex(parts(3)), 2) & _
                         Right("00" & Hex(parts(2)), 2) & _
                         Right("00" & Hex(parts(1)), 2))
   
End Function


Public Function SocketsCleanup() As Boolean

    Dim X As Long
   
    X = WSACleanup()
   
    If X <> 0 Then
        MsgBox "Windows Sockets error " & Trim$(Str$(X)) & _
               " occurred in Cleanup.", vbExclamation
        SocketsCleanup = False
    Else
        SocketsCleanup = True
    End If
   
End Function


Public Function SocketsInitialize() As Boolean

    Dim WSAD As WSADATA
    Dim X As Integer
    Dim szLoByte As String, szHiByte As String, szBuf As String
   
    X = WSAStartup(WS_VERSION_REQD, WSAD)
   
    If X <> 0 Then
        MsgBox "Windows Sockets for 32 bit Windows " & _
               "environments is not successfully responding."
        SocketsInitialize = False
        Exit Function
    End If
   
    If LoByte(WSAD.wVersion) < WS_VERSION_MAJOR Or _
       (LoByte(WSAD.wVersion) = WS_VERSION_MAJOR And _
        HiByte(WSAD.wVersion) < WS_VERSION_MINOR) Then
       
        szHiByte = Trim$(Str$(HiByte(WSAD.wVersion)))
        szLoByte = Trim$(Str$(LoByte(WSAD.wVersion)))
        szBuf = "Windows Sockets Version " & szLoByte & "." & szHiByte
        szBuf = szBuf & " is not supported by Windows " & _
                          "Sockets for 32 bit Windows environments."
        MsgBox szBuf, vbExclamation
        SocketsInitialize = False
        Exit Function
       
    End If
   
    If WSAD.wMaxSockets < MIN_SOCKETS_REQD Then
        szBuf = "This application requires a minimum of " & _
                 Trim$(Str$(MIN_SOCKETS_REQD)) & " supported sockets."
        MsgBox szBuf, vbExclamation
        SocketsInitialize = False
        Exit Function
    End If
   
    SocketsInitialize = True
       
End Function
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LVL 3

Expert Comment

by:Lewy
ID: 2332443
Try

If Winsock1.LocalIP = "127.0.0.1" Then
    Text1.Text = "Not connected"
Else
    Text1.Text = "Connected"
End If

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Author Comment

by:Goob123
ID: 2332460
Great thanks
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